Abstract：Objective： To conduct a retrospective analysis on the clinical data of treating patients with subacute cough by applying classical formulas based on the theory of “periods of symptom alleviation of six-channel diseases”，and evaluate its clinical effect. Methods：According to the inclusion and exclusion criteria， the clinical data of patients diagnosed as subacute cough at the outpatient of Respiratory and Critical Care Medicine Clinic of Tongde Hospital of Zhejiang Province from September 2021 to March 2022 were collected. The pre- treatment and post- treatment self- control designs were used to compare the changes in scores of Visual Analogue Scale (VAS) of cough，and Cough Evaluation Test (CET) before and after treatment. The clinical effects were evaluated according to the “Guiding Principles for Clinical Research of New Chinese Medicine (Trial)”. Results：A total of 43 cases were included. With the criteria of “periods of symptom alleviation of six-channel diseases” and “principle syndrome” serving as the basis for judging six- channel diseases， there were 17 cases of single- channel diseases and 26 cases of multiple-channel diseases. Among single-channel diseases，yangming disease was most commonly seen with 6 cases (35%)，followed by taiyin disease with 4 cases (24%) and jueyin disease with 4 cases (24%). Among multiple-channel diseases ， the most common cases were yangming and taiyin disease with 8 cases (31%) ， taiyin and jueyin disease with 5 cases (19%) ， yangming and shaoyang disease with 4 cases (15%)，and shaoyang and taiyin disease with 3 cases (12%). The top five most frequently used formulas in descending order are Linggan Wuwei Jiangxin Decoction，Wumei Pills，Xiaochaihu Decoction， Baihu Decoction， Xuanfu Daizhe Decoction successively. The VAS score of cough was [7(6， 7)] before treatment and [2(2， 3)] after treatment ， the difference being significant (P ＜ 0.05). The CET score was [15(13，16)] before treatment and [7(6，9)] after treatment，the difference being significant (P＜0.05). After intervention and treatment of Chinese medicine， the total effective rate was 79.1% . Conclusion： Guided by the theory of “periods of symptom alleviation of six- channel diseases”， the use of classical formulas has good clinical effects in treating subacute cough with timed onset.